The present invention relates to keyboards for musical instruments and more particularly to a supporting and pivot device made of plastic. The pivot device has sufficient strength and is capable of slight elastic deformation. It is designed to support the respective key body with the interposition of a lever member so as to articulate said key about a pivot transverse pin or rod supported by the stationary frame of the keyboard so as to permit that said key can be pressed down or struck by a finger against the effect of a return spring, rotating about said pin with a very easy, noiseless, steady and springing-up movement which is perfect in all respects.